I highly doubt there is a good source with any credibility on that...
That is still very much explored today, and who is best on it is much a matter of opinion.

Full touch UIs have only been around for a few years, and there is still lots of room to innovate

Personally, I think the absolute number one important thing for a touch UI is responsiveness.
If an area is functional (button, scrollable, a tab, whatever), it must signal that immediately (within say 100ms) when I touch it. If its not functional it must not signal anything.

Response can come in many forms, highlight, following your finger, vibrations, sparkles flying about, (or just doing the action _immediately_) etc, but if nothing happens, I will constantly be wondering if my action was received, and interaction becomes a hassle.

Then number two is having enough space for fitting my finger

And number three not loading too much functionality into the same screen and having clear icons (to avoid confusion and misclicks)

If that is fulfilled, the UI can look anyway it wants in my professional opinion...

Responsiveness and feeling alive are very important goals I will be aiming for. I am trying to gather anything I can (ideas, experiences, good examples) until I feel I have an idea of the design which "nails" it. So I will keep an eye on this thread with hope for more replies to come up!